Flash-forward to 2004. Celine and Jesse finally reunite in “Before Sunset,” which Delpy co-wrote with Hawke and director Richard Linklater. The movie is an 80-minute tour de force of pure, real-time dialogue, set in a single afternoon in Paris, and it’s a joy. OK, a bittersweet joy. Jesse is now a New York novelist, married with a kid and on a book tour. (His novel happens to be about a whirlwind night with a beautiful French girl.) Celine, a Parisian environmentalist, has the obligatory loft and photojournalist boyfriend. Both have forfeited the youthful idealism that fueled their night together a decade before. This movie doesn’t need an ill-timed rendezvous on a train platform: the supposedly perfect lives these people have built are messy enough. Would it be different if they were together?

Delpy, who’s a revelation in the movie, insists it’s the question–not the answer–that matters. Needless to say, that’s not the formula for a blockbuster. “Before Sunrise” was profitable, but the studio (Castle Rock) didn’t beg for a sequel. Still, Delpy, Linklater and Hawke all thought the characters were too rich not to revisit. Linklater’s first stab at “Before Sunset” tried it Hollywood’s way: it put Celine and Jesse on madcap travels and married them in the end. “I hated that part,” says Delpy. “It became just another film about a relationship, and luckily it wasn’t greenlighted. No one wanted it. It was too conventional.”

Over the next two years, Linklater, Delpy and Hawke collaborated on a new script by e-mail. “These characters were still alive in us,” Linklater says, “and the three of us were compelled in some form or fashion to try and get this done.” Linklater mapped out a budget of less than $3 million–an under-the-radar figure that allowed them creative autonomy. The movie was shot in just 15 days, so every line, every gesture, was meticulously timed to avoid cutting. “Julie and Ethan are really out there naked,” Linklater says. “All you’re watching is these two people slowly reveal how they feel to one another.” And it never would have worked, he adds, without Delpy’s “strength, and her almost intimidating intelligence.”

Golly, just what Hollywood looks for in a leading lady–that and Delpy’s experience working with Jean-Luc Godard. Since she moved to L.A. from her native Paris 12 years ago, the closest Delpy’s come to blockbusterdom is her role as Chris O’Donnell’s girlfriend in the 1993 remake of “The Three Musketeers.” “I have no problem with Hollywood films,” she says. “I just have to find one I really want to be in. I’m not asking for a masterpiece–just a touch of quality.” Next year she hopes to direct a script she’s written based on the true story of a Hungarian countess who bathed in blood. (Look, hope is good.) After that she’d like to try a comedy. She could even try a musical–“Before Sunset” has three of her songs. “It’s difficult for people to understand that you can do more than one thing,” Delpy says. But if all else fails, why not revisit Celine every decade or so? After all, she wrote the part herself, for herself and out of herself. Who says you can’t merge with someone completely?